How to create and save new POJO object based on another one requested from Hibernate+Java

Question

I do have a Java Web Application. It does use hibernate for creating, updating, saving the web form data to database. The task is to create a new record in the database within the same table based on previous record. So, what I have now:

The code:

    //Function which returns a record from database based on UUID

    @Override
public Marriage getMarriageUuId(String uuId) {
    Session session = sessionFactory.getCurrentSession();

    Criteria criteria = session.createCriteria(Marriage.class);
    criteria.add(Restrictions.eq( "uuId", uuId ));

    return (Marriage) criteria.uniqueResult();
}

//function which does save new record
@Override
public Integer addMarriage(Marriage marry) {
    Session session = sessionFactory.getCurrentSession();
    return (Integer) session.save(marry);
}

//the action itself
    Marriage newVersion= caseRegisterService.getMarriageUuId(marriage4.getUuId()); 

                        newVersion.setVoided(false);
                        newVersion.setState("3.EDIT");
                        newVersion.setVersion(oldVersion.getVersion()+1);
                        newVersion.setUuId(newUuId);
   caseRegisterService.addMarriage( newVersion );

I do have UUID and based on this I get some record from the database and assign it to the corresponding object. It's not set as primary key. The primary key is just an auto increment in postgresql . The code works but it just keeps updating the current object with the new data. Instead I want to to create the new record in the database with new data, plus previous data. If I create it the very first time, when it doesn't exist in the database, then it creates that object but after it just keeps updating it.

From what I understand the problem is in primary key . So, when I get back the object from the database it comes back with it's unique primary key , and as the result hibernate just updates it. So, how to reset that primary key for the new object? So, that hibernate will think it's new object. I also dont want to manually increase it, it's not the right way.

Answer 1

As I understand, when we have something like this:

// open session, transaction

 Marriage newVersion= caseRegisterService.getMarriageUuId(marriage4.getUuId()); 
 newVersion.setVoided(false);
 newVersion.setState("3.EDIT");

// close session, transaction

Hibernate will update newVersion (with old uuId ) cause of a session flush, even if you didn't call update() method.

So what you can try to do:

Marriage newVersion= caseRegisterService.getMarriageUuId(marriage4.getUuId()); 

// detach entity from session
session.evict(newVersion);

newVersion.setVoided(false);
newVersion.setState("3.EDIT");
newVersion.setVersion(oldVersion.getVersion()+1);

// reset primary key
newVersion.setId(null);

caseRegisterService.addMarriage( newVersion );

You can use a bit simpler code to load entity:

session.get(Marriage.class, uuId);